The present invention relates to an anti-HSV agent derived from a plant that inhibits the replication of HSV-1 AND HSV-2 and a method for producing a plant-derived substance that has Anti-HSV activity.
Infections by Herpes simplex virus (HSV), Herpes simplex virus Type I, and Herpes simplex virus Type II, affect approximately 50 million Americans and about 500,000 new cases appear each year. Approximately 30 million Americans are infected with genital herpes (American Social Health Association). The HSV virion is a large (100 to 150 m.gamma.), enveloped virus with an icosahedral capsid. It has double stranded DNA with a genome that encodes at least 70 polypeptides. This large amount of regulatory information permits the virus to control its own gene expression and to modify multiple complex events within the infected cell. The herpes simplex virus enters the host by direct contact, is spread to a target tissue only, spreads within the host via neuronal axonal flow, targets the dorsal root ganglia and after recovery of the host from an acute infection, remains latent in the targeted tissue. HSV viruses are difficult to treat because they appear to have a mechanism by which they are able, over several generations of the virus, to adapt to adverse environmental conditions and survive.
Once the virus is transmitted to a susceptible individual, HSV replicates in the epithelial cells of mucosal surfaces. The HSV replication is usually asymptomatic, as evidenced by the many individuals who are seropositive for HSV antibody, but have no history of symptomatic infection. For some individuals the infection can result in severe, ulcerative lesions.
Following replication in epithelia, the virus infects the peripheral endings of the sensory neurons innervating the site of infection, and is transported through the neuronal axons to the nuclei. Viral DNA enters the neuronal nuclei and latent infections are established. Because the latent infection remain in those nerve cells of the body for the lifetime of the host, infection by HSV has the potential to result in many episodes of recurrent disease and transmission.
The use of pharmaceutical and herbal treatments of the HSV-1 and HSV-2 viruses is known in the prior art. More specifically, treatments are focused on HSV-1, the primary cause of cold sores, or HSV-2, the main cause of genital herpes. Epidemiologic studies have suggested that infection by HSV-2, along with other sexually transmitted diseases that cause genital ulcers, increases the risk of acquisition of HIV. The mechanism of this increased risk is unknown, but it may be due to the increased numbers of HIV-susceptible cells (CD4+ T cells and macrophages) present in genital epithelium during inflammatory immune responses generated by the STDs (Latif et al. 1989).
The treatments currently available help the host immune system to help itself in coping with the herpes virus. Most of the present treatments are focused upon preventing the fusion of the virion envelope with the host cell plasma membrane by negatively influencing host cell membrane receptors or by interfering with the glycosylation of viral protein required for fusion, and by reducing viral replication within the host cell nucleus. There are a number of antiviral drugs available for inhibition of HSV replication, including acyclovir, gancyclovir and foscarnet. Three of the most popular medications prescribed to treat genital herpes are: Acyclovir, Famciclovir and Valacyclovir.
Acyclovir (ACV), 9-[(2-hydroxyethoxy)methyl]guanine, is a major antiviral drug which has been used in the treatment of a variety of herpes virus infections. It can be administered as topical, oral, or intravenous preparations, the topical preparations being less effective. Acyclovir therapy is associated with very few adverse effects. Valaciclovir or L-valine ester of acyclovir is a prodrug of acyclovir. The antiherpes virus agent penciclovir, 9-(4-hydroxy-3-hydroxymethylbut-1-yl)-guanine, has a spectrum of activity against human herpes viruses similar to that of acyclovir. Famciclovir, the 6-deoxy derivative of penciclovir, is converted to penciclovir in the body by means of oxidative metabolism.
Nucleoside analogues such as the guanosine analogues acyclovir, valaciclovir, penciclovir and famciclovir have a more narrow antiviral spectrum than foscarnet and mainly show effect against HSV-1 and HSV-2 and VZV viruses. These compounds do not act directly on the viral DNA polymerase like foscarnet, but have to be phosphorylated three times by viral and cellular enzymes for inhibition of the viral polymerase to be achieved. They are primarily administered as oral compositions although other ways of administration, such as parenteral, are also possible. Some problems in treating herpes virus infections by parenteral administration are the high doses and large volumes to be administered and the short half-life of the antiviral compound in the circulation. Further, they require daily administration of the drugs for long periods of time. The clinical effectiveness of the nucleoside analogues acyclovir, valaciclovir, penciclovir and famciclovir on recurrent cutaneous virus diseases is, as with foscarnet, limited. With topical treatment, the healing time is only reduced by approximately two to three days.
It should be noted that all of the above drugs target replication of the viral DNA following infection of susceptible cells. They have been shown ineffective at reducing viral replication in genital epithelium when applied topically after infection has proceeded to the extent of causing lesions. Reduction of epithelial replication during initial infection has been demonstrated in animal models to reduce the amount of latent virus present in ganglia and to reduce the frequency and severity of recurrent disease. However, other studies have demonstrated that epithelial replication is not a prerequisite for the establishment of latent infection in animal models. Further, the high percentage of women with latent virus but no history of symptomatic infection suggests that in humans, high levels of replication may not be necessary for the establishment of latency.
In addition to the drugs that are set out above, many herbal treatments are being used and their effectiveness continuously being studied. The active ingredient in most herbs is an alkaloid, a very toxic molecule if taken in considerable excess. There are several herbs that are more than a match for most viruses, examples being; lavender, myrrh and sage.
There are even instances where natural essential oils have strong powerful results against the HSV virus on contact. The active ingredients vary from Terpenes, Sesquiterpenes through to Ketones, Aldehydes, Esters, to Alcohols, and phenols. Generally, the essential oils are the refined active ingredients from flowers, leaves and roots of plants. The most commonly used are lavender, basil, calendula, lemon, tee tree, cinnamon, citronella, clove, eucalyptus, geranium, niqouli, oregano, peppermint, thyme, ginger, patchouli, cedar wood, Melissa, cajeput, rosemary and many others.
The results of this resurgence in the use of herbal and natural products, has prompted numerous studies to investigate the biological basis for medicinal properties associated herbals. One such plant product that has potential medicinal properties is an extract of pinecones. The pine cone extract has been reported to have an ameliorative effect on a variety of infectious diseases and on several tumors.
The alkaline extraction of a pinecone is taught by U.S. Pat. No. 4,985,249. In that patent alkaline extraction is followed by pH 5 precipitation to yield a fraction known and PC6; further precipitation by alcohol resulted in another fraction termed PC7. The active components of both fractions, PC6 and PC7, have been shown to contain lignins or polyphenylpropenoids covalently linked with polysaccharides. Further, U.S. Pat. No. 4,985,249 has been proven to have inhibitory activity in vitro against human immunodeficiency virus (HIV) replication.
In order to provide an effective treatment to reduce the levels of replication of HSV-1 and HSV-2 following the primary and reactivated infections, the present inventors have assessed the anti-HSV activity of potassium hydroxide extract of pine cone.
The addition of potassium with the pine cone extract improves the general health benefits of the anti-HSV agent. It is known that potassium is an extremely important electrolyte in the body that functions in the maintenance of: water balance and distribution; acid-base balance; muscle and nerve cell function; heart function, and kidney and adrenal function.
Therefore, it can be appreciated that there exists a continuing need for a new and improved anti HSV agent which can be used to solve the problem of viral replication and reactivation which remains unsolved by the prior art. In this regard, the present invention fulfills this need.
The present invention is a method of inhibiting replication of HSV-1 AND HSV-2 using an anti-HSV agent derived from a plant viz a potassium hydroxide extraction method for producing an extract of pine cone that has anti-HSV activity and contains potassium.
After extensive study and testing the inventor discovered that, a high yield of extract from pinecone is obtained by using a potassium hydroxide solution. Further, the inventor discovered that the resulting extract, termed the polyphenylpropenoid-polysaccharide complex (PPC or PCE) has antiviral activity. Accordingly, a primary function of the present invention is to provide a plant-derived substance, which has potent anti-HSV activity.
Another object of the present invention is to provide a method of inhibiting replication of HSV-1 AND HSV-2 using the plant-derived anti-HSV agent.
Still another object of the present invention is to provide a method for obtaining the anti-HSV substance from pine cones.
An even further object of the present invention is to provide an anti-HSV agent which includes potassium.
It is the object of the invention to provide a method for the production of a pine cone extract. It is a further object of the invention to provided a pine cone extract produced by that method.
The anti-HSV agent of the present invention is characterized in that said agent contains a potassium hydroxide extract of various pine cones such as Pinus parviflroa Sieb. Et Zucc., especially high molecular weight anti-HSV substances of this extract. The high molecular weight anti-HSV substances describe above can be obtained by extraction of the pine cone with a potassium hydroxide solution.
A further object of the present invention is to provide a new and improved method of inhibiting replication of HSV-1 AND HSV-2 using an ANTI-HSV agent which may be easily and efficiently manufactured and marketed.
An even further object of the present invention is to provide a method for producing a potassium hydroxide extract of pine cone that has anti-HSV activity which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such method of producing a pine cone extract with anti-HSV activity economically available to the buying public.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated the preferred embodiments of the invention.